Vacuum infusion bag film structure of wind power generation blade

Abstract

The invention discloses a vacuum infusion bag film structure of a wind power generation blade. The vacuum infusion bag film structure of the wind power generation blade comprises at least one bag film, the bag film comprises a base material layer and a temperature-sensitive color-changing layer, the temperature-sensitive color-changing layer is arranged on the base material layer or embedded in the base material layer, and the temperature-sensitive color-changing layer is configured to change color along with temperature change. The temperature-sensitive color-changing layer is used for monitoring local temperature abnormity in the vacuum infusion process of the wind power generation blade, when the temperature of the coverage area of the temperature-sensitive color-changing layer exceeds a preset threshold value, the temperature-sensitive color-changing layer is converted into a second color from a first color, and the first color is different from the second color. According to the technical scheme provided by the invention, the temperature-sensitive color-changing layer is arranged on the bag film, so that a real-time and visual temperature monitoring means can be provided when the leaves are heated and cured or maintained and heated.

Description

Technical Field

[0001] The present application relates to the technical field of wind power blades, and in particular to a vacuum infusion bag film structure for wind power blades. Background Art

[0002] In the manufacturing process of wind turbine blades, vacuum infusion is a commonly used composite molding method. The vacuum infusion process injects resin into pre-laid fiber reinforcement materials and cures them in a vacuum environment, ultimately forming a high-strength composite structure.

[0003] However, during the vacuum infusion and curing process, the exothermic reaction of the resin may cause local temperatures to be too high. Traditional temperature monitoring methods (such as thermocouples or infrared temperature measurement) can usually only achieve "point" or "line" monitoring, which makes it difficult to cover the entire surface of the wind turbine blade. There are monitoring blind spots, resulting in high quality risks and production costs in the manufacturing process of wind turbine blades. Summary of the Invention

[0004] The purpose of this application is to provide a vacuum infusion bag film structure for wind turbine blades. By setting a temperature-sensitive color-changing layer on the bag film, a real-time and visual temperature monitoring method can be provided when the blades are heated for curing or maintained.

[0005] The present invention provides a wind turbine blade vacuum infusion bag film structure, comprising:

[0006] At least one bag film, the bag film comprising a substrate layer and a temperature-sensitive color-changing layer, the temperature-sensitive color-changing layer being disposed on the substrate layer or embedded in the substrate layer;

[0007] The temperature-sensitive color-changing layer is configured to change color due to temperature changes, and is used to monitor local temperature anomalies during the vacuum infusion process of wind turbine blades. When the temperature of the area covered by the temperature-sensitive color-changing layer exceeds a preset threshold, the temperature-sensitive color-changing layer changes from a first color to a second color, and the first color and the second color are different.

[0008] Beneficial effects: This wind turbine blade vacuum infusion bag film structure has a base material layer on the bag film, which can ensure that the bag film has good sealing and mechanical strength. By providing a temperature-sensitive color-changing layer on the bag film, a real-time, visual temperature monitoring method can be provided when the blade is heated for curing or maintained and heated. The temperature-sensitive color-changing layer can cover the entire bag film or a part of the bag film, so that when the bag film is attached to the surface of the wind turbine blade, the covered area of the temperature-sensitive color-changing layer can be used to monitor local temperature anomalies during the vacuum infusion process of the wind turbine blade. Once the surface temperature of the covered area of the temperature-sensitive color-changing layer exceeds the preset threshold, the color changes from the first color to the second color (for example, from light color to dark color), and the operator can intuitively see the color-changing area, thereby realizing comprehensive and real-time temperature monitoring of the surface of the wind turbine blade, and avoiding the neglect of local overheating problems due to monitoring blind spots.

[0009] During the vacuum infusion and curing process, the exothermic reaction of the resin can easily cause localized overheating. This bag-film structure rapidly responds to temperature changes. If the local temperature rises abnormally above a preset threshold, the area covered by the thermochromic layer immediately changes color, providing a timely warning to the operator. This enables prompt detection of localized temperature anomalies, allowing operators to intervene promptly, effectively avoiding quality issues caused by localized overheating, reducing blade defect rates, improving product quality, and ensuring the reliability and stability of wind turbine blades in actual operation.

[0010] Furthermore, using this bag-film structure for temperature monitoring eliminates the need for complex equipment installation and commissioning. Operators can simply observe the color change of the bag film to determine the blade temperature. Compared to traditional monitoring methods that require wiring of thermocouples and specialized equipment, calibration, and maintenance, this bag-film structure simplifies the process and reduces equipment procurement, installation, and maintenance costs.

[0011] Furthermore, the bag film structure is used in much the same way as conventional bag films, requiring no changes to the vacuum extraction, laying method, or curing process. Simply adding a temperature-sensitive color-changing layer to the multi-layer structure of the bag film itself is sufficient, requiring minimal process changes and facilitating large-scale adoption.

[0012] In an optional embodiment, the thermochromic layer is a reversible color-changing layer. When the surface temperature of the covered area of the thermochromic layer drops from a state exceeding the preset threshold to below the preset threshold, the color of the covered area of the thermochromic layer changes from the second color to the first color.

[0013] Beneficial Effects: During wind turbine blade production, resin curing is a dynamic process, with temperatures constantly fluctuating. The reversible thermochromic layer tracks temperature changes in real time. When the temperature in the area covered by the thermochromic layer exceeds a preset threshold, the color changes from the first color to the second color, alerting the operator to a temperature anomaly. When the temperature returns to normal, the color changes back to the first color. This allows operators to continuously monitor temperature fluctuations and identify potential problems promptly. During the early stages of resin curing, due to the intense chemical reaction, local temperatures may fluctuate frequently. The reversible color change feature allows operators to monitor temperature conditions at all times, ensuring that the entire curing process remains within the optimal temperature range. If temperature anomalies are detected during production, operators can take measures to reduce the temperature. Once the temperature returns to normal and the reversible thermochromic layer returns to its first color, they can continue with subsequent operations. This eliminates the need to wait for the entire production process to complete inspections and adjustments. This avoids production interruptions and delays caused by temperature issues and improves production efficiency.

[0014] The reversible color change feature helps operators analyze temperature trends. By observing the frequency and duration of color changes, the severity and duration of temperature anomalies can be determined. Frequent color changes in a particular area indicate significant temperature fluctuations, possibly due to poor heat dissipation or other issues. Prolonged color changes indicate a more severe temperature anomaly, requiring timely adjustment of process parameters.

[0015] In an optional embodiment, the thermochromic layer is an irreversible color-changing layer. When the surface temperature of the covered area of the thermochromic layer drops from a state exceeding the preset threshold to below the preset threshold, the color of the covered area of the thermochromic layer remains the second color.

[0016] Beneficial Effects: The irreversible color-changing layer accurately records when the temperature exceeds a preset threshold. Regardless of subsequent temperature fluctuations, the discolored area maintains its second color, providing a visual and unalterable record of temperature anomalies during the production process. This helps operators clearly understand which parts of the blade experienced temperature issues, as well as the approximate severity and scope of the issues, during subsequent quality inspections and analysis, facilitating tracing and troubleshooting of potential quality risks.

[0017] The reversible color-changing layer's preset threshold temperature is generally between 50° and 80°. If the wind turbine blade temperature exceeds 80°, the reversible color-changing layer will exceed its preset threshold and will not change color to alert the operator. The irreversible color-changing layer's preset threshold temperature can be flexibly set above 80°. When the wind turbine blade temperature exceeds 80°, the irreversible color-changing layer will change color according to its preset threshold above 80° to alert the operator, preventing the bag film from being damaged by high temperatures and causing rupture.

[0018] In an optional embodiment, at least two bag films are provided, and at least two bag films are sequentially sleeved;

[0019] Wherein, the temperature-sensitive color-changing layer of at least one of the bag films is a reversible color-changing layer, and the temperature-sensitive color-changing layer of at least one of the bag films is an irreversible color-changing layer.

[0020] Beneficial Effects: The reversible color-changing layer typically has a preset threshold temperature between 50° and 80°C, while the irreversible color-changing layer can have a preset threshold temperature above 80°C. The combination of the two enables effective monitoring over a wider temperature range. Under normal temperature fluctuations, the reversible color-changing layer provides real-time feedback on temperature changes, allowing operators to understand whether the temperature is fluctuating within a normal range. However, when the temperature exceeds the higher range of 80°C, the irreversible color-changing layer takes effect, filling the gap in the reversible color-changing layer's monitoring capabilities in the high-temperature range and ensuring effective monitoring of the wind turbine blades throughout their entire temperature range.

[0021] By observing the color changes of the reversible and irreversible color-changing layers on different bag films, operators can more accurately identify potential problems with wind turbine blades. For example, if the reversible color-changing layer indicates normal temperature, but the irreversible color-changing layer has changed color, it indicates that the blade may have experienced a brief period of abnormally high temperature.

[0022] Using at least two bag films, each with a reversible and irreversible color-changing layer, adds redundancy to the temperature monitoring system. Even if one bag film or color-changing layer fails or is disrupted by external factors, the other bag film and color-changing layer will continue to function normally and provide temperature information, ensuring the reliability of the entire monitoring system and reducing the risk of safety accidents caused by monitoring failure.

[0023] In an optional embodiment, the temperature-sensitive color-changing layer is provided on the outer surface of the substrate layer.

[0024] Beneficial Effects: The thermochromic layer, located on the outer surface, directly contacts the external environment or the monitored object, enabling faster and more accurate sensing of temperature changes. This eliminates the need for heat transfer through an intermediate medium, such as a substrate layer, reducing heat loss and delay during heat transfer. This allows the thermochromic layer to more sensitively detect subtle temperature changes, improving temperature monitoring accuracy. The outer surface of the thermochromic layer is also more easily observable, allowing users to directly and intuitively obtain color change information from the outside.

[0025] In an optional embodiment, the temperature-sensitive color-changing layer is provided on the outer surface of the substrate layer by spraying, printing or hot pressing.

[0026] Beneficial Effects: By spraying the thermochromic layer onto the outer surface of the substrate layer, the layer can be evenly coated, ensuring accurate and consistent temperature monitoring. By adjusting the number of spraying cycles, coating concentration, and spraying equipment parameters, the thickness of the thermochromic layer can be easily controlled to meet varying temperature sensitivity and application requirements. Furthermore, the spraying method is relatively fast and suitable for large-scale production. It can be applied to a large number of substrates in a short period of time, improving production efficiency and reducing production costs.

[0027] Thermochromic pigments are dispersed in ink and applied to the outer surface of the substrate layer by printing, which can achieve local pattern printing (such as temperature warning signs) or full coverage printing for personalized design.

[0028] The existing temperature-sensitive color-changing layer can be bonded to the outer surface of the substrate layer by hot pressing, which is beneficial for controlling the distribution of material quality, and can be bonded to a partial area of the substrate layer as required.

[0029] In an optional embodiment, the bag film further includes a protective layer, and the protective layer is covered on the outer surface of the temperature-sensitive color-changing layer.

[0030] Beneficial effect: In actual use, the surface of the bag film may be scratched by tools or other parts. By providing a protective layer on the outer surface of the temperature-sensitive color-changing layer, the temperature-sensitive color-changing layer is prevented from being directly worn and scratched, thereby maintaining the integrity and performance of the temperature-sensitive color-changing layer.

[0031] In an optional embodiment, the temperature-sensitive color-changing layer and the substrate layer are co-extruded to form the bag film, and the temperature-sensitive color-changing layer is embedded in the substrate layer.

[0032] Beneficial effects: Multi-layer co-extrusion allows the temperature-sensitive color-changing layer and the base material layer to fuse with each other at the molecular level to form a tight whole, which can significantly improve the adhesion between the two layers and effectively prevent the temperature-sensitive color-changing layer from falling off or peeling during use, ensuring the stability and integrity of the bag film structure.

[0033] During the multi-layer co-extrusion process, the temperature-sensitive color-changing layer can be evenly embedded in the base material layer, avoiding the situation of local excessive thickness or thinness, ensuring the consistency and stability of the temperature-sensitive color-changing function on the entire bag film surface, so that the bag film can accurately sense the temperature at different positions and show corresponding color changes.

[0034] The thermochromic layer is embedded within the substrate layer, which provides physical protection for the layer, shielding it from direct environmental influences such as abrasion, scratching, UV radiation, and chemical corrosion. This helps maintain the performance of the thermochromic layer, extending its service life and ensuring it can accurately respond to temperature during long-term use.

[0035] In addition, multi-layer co-extrusion is a continuous processing technology that can complete the composite of the temperature-sensitive color-changing layer and the substrate layer in one operation, greatly improving production efficiency and reducing production costs.

[0036] In an optional embodiment, the material of the substrate layer is a thermoplastic polymer.

[0037] Beneficial effects: The thermoplastic polymer can be nylon, polyethylene, ethylene-vinyl acetate copolymer, etc. Nylon has excellent mechanical strength and wear resistance. The bag film made from it can withstand large tension and friction and is not easy to break or damage.

[0038] Polyethylene has high chemical stability and is not easily corroded. It also has good transparency. The bag film made from it allows the wind turbine blades inside the bag film to be clearly seen. When the color of the bag film changes, the operator can technically observe the color change.

[0039] Ethylene-vinyl acetate copolymer has good elasticity and softness, and can seal quickly and firmly during the heat sealing process, forming a good sealing effect to prevent the bag film from leaking. At the same time, the high heat sealing strength can ensure the sealing and integrity of the bag film during use.

[0040] Polyester has extremely high transparency and glossiness, as well as high strength, hardness and rigidity. The bag film can withstand greater pressure and weight, is not easily deformed, and can provide reliable support and protection for the items in the bag film.

[0041] In an optional embodiment, the thickness of the substrate layer is 30 μm-150 μm.

[0042] Beneficial Effects: When the base material layer is 30μm thick or thicker, it provides sufficient structural support for the bag film, giving it excellent tensile strength and tear resistance. It is less likely to break or rupture during use and can withstand items of a certain weight and a certain degree of external force, such as compression and friction. A thickness of no more than 150μm ensures that the bag film does not become too brittle due to excessive thickness, while maintaining good flexibility and folding resistance, making it easy to fold and seal. It can also buffer energy by deforming when subjected to external forces, reducing the risk of rupture. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0044] Figure 1 This is a cross-sectional view of a vacuum infusion bag film structure of a wind turbine blade according to an embodiment of the present application;

[0045] Figure 2 This is a cross-sectional view of a vacuum infusion bag membrane structure for a wind turbine blade in another embodiment provided in the present application.

[0046] Description of reference numerals:

[0047] 100, bag film; 110, base material layer; 120, temperature-sensitive color-changing layer; 130, protective layer. DETAILED DESCRIPTION

[0048] Vacuum infusion is a commonly used composite material molding method in the manufacture of wind turbine blades. However, during the vacuum infusion and curing process, the exothermic reaction of the resin can cause localized overheating. Traditional temperature monitoring methods (such as thermocouples or infrared temperature measurement) typically only provide "point-based" or "line-based" monitoring, making it difficult to cover the entire surface of the wind turbine blade. This creates blind spots and results in significant quality risks and production costs during wind turbine blade manufacturing.

[0049] To address this issue, the inventors installed a large number of sensors around the blades to monitor their temperature, reducing blind spots in surface temperature monitoring during wind turbine blade manufacturing. Due to the large size of wind turbine blades, the large number of sensors required increased production costs and made equipment maintenance more difficult.

[0050] Based on this, the inventors of the present application have invented a vacuum infusion bag film structure for wind turbine blades. By providing a temperature-sensitive color-changing layer on the bag film, a real-time, visual temperature monitoring method can be provided when the blades are heated for curing or maintained. The temperature-sensitive color-changing layer can cover the entire bag film or a portion of the bag film, so that when the bag film is attached to the surface of the wind turbine blade, the area covered by the temperature-sensitive color-changing layer can be used to monitor local temperature anomalies during the vacuum infusion process of the wind turbine blade. Once the surface temperature of the area covered by the temperature-sensitive color-changing layer exceeds a preset threshold, the color changes from the first color to the second color (for example, from a light color to a dark color), and the operator can intuitively see the color-changing area, thereby realizing comprehensive and real-time temperature monitoring of the surface of the wind turbine blade, and avoiding the problem of local overheating being ignored due to monitoring blind spots.

[0051] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0052] In order to solve the above technical problems, the following Figures 1 to 2 , describing embodiments of the present invention.

[0053] According to an embodiment of the present invention, on the one hand, Figures 1 to 2 As shown, a wind turbine blade vacuum infusion bag film structure is provided, including a bag film 100, and the bag film 100 is provided with at least one.

[0054] Specifically, if Figure 1 and Figure 2 As shown, the bag film 100 includes a substrate layer 110 and a temperature-sensitive color-changing layer 120 , wherein the temperature-sensitive color-changing layer 120 is disposed on the substrate layer 110 , or the temperature-sensitive color-changing layer 120 is embedded in the substrate layer 110 .

[0055] Specifically, the temperature-sensitive color-changing layer 120 is configured to change color due to temperature changes, and is used to monitor local temperature anomalies during the vacuum infusion process of wind turbine blades. When the temperature of the area covered by the temperature-sensitive color-changing layer 120 exceeds a preset threshold, the temperature-sensitive color-changing layer 120 changes from a first color to a second color, and the first color and the second color are different.

[0056] This wind turbine blade vacuum infusion bagging structure features a base material layer 110 on the bagging film 100, which ensures the bagging film 100 has excellent sealing and mechanical strength. By providing a temperature-sensitive color-changing layer 120 on the bagging film 100, a real-time, visual temperature monitoring method can be provided during blade heating, curing, or maintenance. The temperature-sensitive color-changing layer 120 can cover the entire bagging film 100 or a portion of the bagging film 100. When the bagging film 100 is attached to the surface of a wind turbine blade, the area covered by the temperature-sensitive color-changing layer 120 can be used to monitor local temperature anomalies during the wind turbine blade vacuum infusion process. Once the surface temperature of the area covered by the temperature-sensitive color-changing layer 120 exceeds a preset threshold, the color changes from a first color to a second color (e.g., from a light color to a dark color). The operator can visually see the color-changing area, achieving comprehensive, real-time temperature monitoring of the wind turbine blade surface and preventing local overheating issues from being overlooked due to monitoring blind spots.

[0057] During the vacuum infusion and curing process, the exothermic reaction of the resin can easily cause localized overheating. This bag-film structure rapidly responds to temperature changes. If the local temperature rises abnormally above a preset threshold, the area covered by the thermochromic layer 120 immediately changes color, providing a timely warning to the operator. This enables timely detection of localized temperature anomalies, allowing operators to intervene promptly, effectively avoiding quality issues caused by localized overheating, reducing the defective rate of wind turbine blades, improving product quality, and ensuring the reliability and stability of wind turbine blades in actual operation.

[0058] Furthermore, using this bag-film structure for temperature monitoring eliminates the need for complex equipment installation and commissioning. Operators can simply observe the color change of the bag film 100 to determine the temperature of the wind turbine blades. Compared to traditional monitoring methods that require wiring of thermocouples and specialized equipment, calibration, and maintenance, this bag-film structure simplifies the process and reduces equipment procurement, installation, and maintenance costs.

[0059] Furthermore, the bag film structure is used in essentially the same manner as conventional bag film 100, requiring no changes to the vacuum extraction, laying method, or curing process. Simply adding a temperature-sensitive color-changing layer 120 to the multi-layer structure of the bag film 100 itself is sufficient, requiring minimal process changes and facilitating large-scale adoption.

[0060] Specifically, the substrate layer 110 may be made of a high-temperature resistant polymer, such as nylon, polyethylene, etc. In the embodiment of the present application, there is no specific limitation on the material of the substrate layer 110 .

[0061] Specifically, the thermochromic layer 120 is a functional layer that is sensitive to temperature changes and can visually display temperature information through color changes. Primarily composed of heat-sensitive pigments / microcapsules and a binder or dispersion medium, the thermochromic layer 120 achieves color changes through specific chemical reactions or physical changes, offering a variety of properties and application advantages.

[0062] Specifically, the thermochromic layer 120 can be coated on the outer surface of the substrate layer 110. The outer surface of the substrate layer 110 can be entirely coated with the thermochromic layer 120, or only partially coated with the thermochromic layer 120. In the embodiment of the present application, there is no specific limitation on the coverage of the thermochromic layer 120 and the substrate layer 110. Specifically, the thermochromic layer 120 can also be embedded in the substrate layer 110.

[0063] It should be noted that the first color and the second color are different. The first color represents the color of the bag film 100 under normal wind turbine blade temperatures, while the second color represents the color of the bag film 100 when the temperature exceeds a preset threshold. In actual production, if the temperature-sensitive color-changing layer 120 of the bag film 100 is set to a light color, such as light blue, under normal conditions, and the temperature changes to a darker color, such as deep black, when the local temperature exceeds a preset threshold, such as 60°C, the temperature-sensitive color-changing layer 120 will be clear. Operators can quickly detect temperature anomalies from the obvious color change and can intuitively determine which areas on the wind turbine blade surface are overly hot without the need for additional complex equipment or data analysis.

[0064] Specifically, the choice of primary and secondary colors can be adjusted based on actual production scenarios and needs. For wind turbine blade materials or production processes that are sensitive to temperature fluctuations, a higher-contrast color combination, such as yellow and red, can be selected to make the temperature change display more eye-catching. For situations where different temperature ranges need to be distinguished, multiple secondary colors can be set to correspond to different temperature thresholds, providing operators with more detailed temperature information and helping them more accurately control the production process.

[0065] In one embodiment, the temperature-sensitive color-changing layer 120 is a reversible color-changing layer. When the surface temperature of the area covered by the temperature-sensitive color-changing layer 120 drops from a state exceeding a preset threshold to below a preset threshold, the color of the area covered by the temperature-sensitive color-changing layer 120 changes from the second color to the first color.

[0066] During wind turbine blade production, resin curing is a dynamic process, with temperatures constantly fluctuating. The reversible thermochromic layer 120 tracks temperature changes in real time. When the temperature in the area covered by the thermochromic layer 120 exceeds a preset threshold, the color changes from the first color to the second color, alerting the operator to a temperature anomaly. When the temperature returns to normal, the color changes back to the first color. This allows operators to continuously monitor temperature fluctuations and identify potential problems promptly. During the early stages of resin curing, due to the intense chemical reaction, local temperatures may fluctuate frequently. The reversible color change feature allows operators to monitor temperature conditions at all times, ensuring that the entire curing process remains within the appropriate temperature range. If a temperature anomaly is detected during production, the operator can take measures to reduce the temperature. Once the temperature returns to normal and the reversible thermochromic layer 120 returns to its first color, subsequent operations can resume. This eliminates the need to wait for the entire production process to complete inspections and adjustments. This avoids production interruptions and delays caused by temperature issues, improving production efficiency.

[0067] The reversible color change feature helps operators analyze temperature trends. By observing the frequency and duration of color changes, the severity and duration of temperature anomalies can be determined. Frequent color changes in a particular area indicate significant temperature fluctuations, possibly due to poor heat dissipation or other issues. Prolonged color changes indicate a more severe temperature anomaly, requiring timely adjustment of process parameters.

[0068] Specifically, wind turbine blade production is typically large-scale and continuous. The reversible temperature-sensitive color-changing layer 120 can be used multiple times, effectively monitoring the temperature during each production cycle. Compared to one-time or irreversible monitoring methods, this significantly reduces production costs. For example, if a production line produces multiple wind turbine blades per day, using irreversible color-changing bag film 100 would require replacing the bag film 100 each time, which is very costly. However, the reversible color-changing bag film 100 can be used repeatedly, and only needs to ensure its stable performance to continue serving production.

[0069] Specifically, the material of the reversible color-changing layer can be an inorganic thermochromic material, an organic thermochromic material, etc. In the embodiment of the present application, the material of the reversible color-changing layer is not specifically limited.

[0070] For example, the reversible color-changing layer can be made of pure VO2, an inorganic thermochromic material, whose color changes with temperature and composition. Within a certain temperature range, the color can reversibly change from colorless, light yellow to dark blue.

[0071] For example, the material of the reversible color-changing layer can be selected from spiropyrans, which are organic thermochromic materials. At different temperatures, the molecular structure will switch between a spiro ring structure and an open ring structure, resulting in a color change, such as from colorless to blue or purple.

[0072] In one embodiment, the temperature-sensitive color-changing layer 120 is an irreversible color-changing layer. When the surface temperature of the area covered by the temperature-sensitive color-changing layer 120 drops from a state exceeding a preset threshold to below a preset threshold, the color of the area covered by the temperature-sensitive color-changing layer 120 remains the second color.

[0073] The irreversible color-changing layer accurately records when the temperature exceeds a preset threshold. Regardless of subsequent temperature fluctuations, the discolored area maintains its second color, providing a visual and unalterable record of temperature anomalies during the production process. This helps operators clearly understand which parts of the wind turbine blade experienced temperature issues, as well as the approximate severity and scope of the issues, during subsequent quality inspections and analysis, facilitating tracing and troubleshooting of potential quality risks.

[0074] The preset threshold temperature of the reversible color-changing layer is generally between 50° and 80°. If the temperature of the wind turbine blade exceeds 80°, the reversible color-changing layer will not change color according to the established color-changing mechanism to alert the operator because it exceeds the preset threshold range. The preset threshold temperature of the irreversible color-changing layer can be flexibly set to exceed 80°. When the temperature of the wind turbine blade exceeds 80°, the irreversible color-changing layer will change color according to its preset threshold above 80° to alert the operator, preventing the bag film 100 from being damaged by high temperature and causing rupture.

[0075] Irreversible color-changing layers can be made from a wide variety of materials, including phosphates, sulfates, nitrates, oxides, and sulfides of lead, nickel, chromium, zinc, cobalt, iron, cadmium, strontium, magnesium, barium, molybdenum, and manganese, as well as methyl violet, phenol compounds, acid clays, azo pigments, and arylmethane pigments. Specifically, a high-temperature-resistant fluorane fuel can be used as a leuco dye, and p-toluenesulfonic acid can be used as a color developer. These microencapsulated materials can be used to monitor a one-time temperature indicator around 100°C.

[0076] In one embodiment, at least two bag films 100 are provided, and the at least two bag films 100 are sequentially stacked. Among them, the temperature-sensitive color-changing layer 120 of at least one bag film 100 is a reversible color-changing layer, and the temperature-sensitive color-changing layer 120 of at least one bag film 100 is an irreversible color-changing layer.

[0077] The reversible color-changing layer typically has a preset threshold temperature between 50° and 80°C, while the irreversible color-changing layer can exceed 80°C. The combination of the two allows for effective monitoring over a wider temperature range. Under normal temperature fluctuations, the reversible color-changing layer provides real-time feedback on temperature changes, allowing operators to understand whether the temperature is fluctuating within a normal range. However, when the temperature exceeds the higher range of 80°C, the irreversible color-changing layer takes effect, filling the gap in the reversible color-changing layer's monitoring capabilities in the high-temperature range and ensuring effective monitoring of the wind turbine blade's entire temperature range.

[0078] By observing the color changes of the reversible and irreversible color-changing layers on different bag films 100, operators can more accurately determine potential problems with wind turbine blades. For example, if the reversible color-changing layer indicates a normal temperature, but the irreversible color-changing layer has changed color, it indicates that the blade may have experienced a brief period of abnormally high temperature.

[0079] Using at least two bag films 100, each with a reversible and irreversible color-changing layer, provides redundancy to the temperature monitoring system. Even if one bag film 100 or one color-changing layer fails or is disrupted by external factors, the remaining bag film 100 and color-changing layer will continue to function normally and provide temperature information, ensuring the reliability of the entire monitoring system and reducing the risk of safety accidents caused by monitoring failure.

[0080] For example, taking two bag films 100 as an example, one bag film 100 is put on the other bag film 100. One bag film 100 is a reversible color-changing layer, and the other bag film 100 is an irreversible color-changing layer. The reversible color-changing layer is responsible for monitoring changes within the normal operating temperature range, allowing operators to understand the real-time temperature status of the blades at any time and judge whether the operation is normal. The irreversible color-changing layer focuses on monitoring high temperature abnormalities. As long as the temperature exceeds 80°C, a color change record will be left. Regardless of how the temperature changes subsequently, it can provide operators with clear evidence that the blades have experienced high temperatures. Among them, the second color of the reversible color-changing layer of the bag film 100 can be black, and the second color of the irreversible color-changing layer of the bag film 100 can be red. The two colors are different, and the operator can directly judge the temperature conditions of the area covered by the temperature-sensitive color-changing layer 120 by the color.

[0081] During the vacuum infusion process, the bag film 100 bonded to the wind turbine blade can be connected to the vacuum vents on the mold. The air inside the bag film 100 can be extracted through the vacuum vents, creating a vacuum state. This removes air from the mold and the surface of the material to be infused, preventing bubbles from forming during infusion and improving the density and quality of the infusion. The remaining bag films 100 can also be connected to the vacuum vents on the mold, responsible for extracting the air between two adjacent bag films 100. Once the air is extracted, the encased bag films 100 can fit tightly together, allowing the bag films 100 not directly bonded to the wind turbine blade to accurately monitor blade temperature. Because the tight fit facilitates heat conduction, the bag film 100's temperature monitoring function is not interfered with by the air layer, accurately reflecting temperature changes in the wind turbine blade and providing reliable data for monitoring and maintaining the operating status of the wind turbine blade.

[0082] In one embodiment, Figure 1 As shown, the temperature-sensitive color-changing layer 120 is disposed on the outer surface of the substrate layer 110 .

[0083] Thermochromic layer 120, located on the outer surface, directly contacts the external environment or the monitored object, enabling faster and more accurate sensing of temperature changes. This eliminates the need for heat transfer through an intermediate medium, such as substrate layer 110, reducing heat loss and delay during heat transfer. This allows the thermochromic layer 120 to more sensitively detect subtle temperature changes, improving temperature monitoring accuracy. Thermochromic layer 120, located on the outer surface, is more easily observable, allowing users to directly and intuitively perceive color change information from the outside.

[0084] Specifically, the temperature-sensitive color-changing layer 120 can be provided on the inner surface of the substrate layer 110, allowing the temperature-sensitive color-changing layer 120 to be directly attached to the wind turbine blade. Alternatively, the temperature-sensitive color-changing layer 120 can be provided on both the inner and outer surfaces of the substrate layer 110. By providing multiple layers of temperature-sensitive color-changing layers 120, when the multiple layers of temperature-sensitive color-changing layers 120 change color simultaneously, the color changes of the multiple layers of temperature-sensitive color-changing layers 120 will be very obvious, which can promptly attract the attention of the operator.

[0085] In one embodiment, the temperature-sensitive color-changing layer 120 is disposed on the outer surface of the substrate layer 110 by spraying, printing, or hot pressing.

[0086] By spraying the thermochromic layer 120 onto the outer surface of the substrate layer 110, the thermochromic layer 120 can be evenly coated on the outer surface of the substrate layer 110, thereby ensuring accurate and consistent temperature monitoring. By adjusting the number of spraying cycles, the coating concentration, and the parameters of the spraying equipment, the thickness of the thermochromic layer 120 can be easily controlled to meet varying temperature sensitivity and usage requirements. Furthermore, the spraying method is relatively fast and suitable for large-scale production. The thermochromic layer 120 can be prepared on a large number of substrates in a relatively short period of time, thereby improving production efficiency and reducing production costs.

[0087] Thermochromic pigments are dispersed in ink and applied to the outer surface of the substrate layer 110 by printing, which can achieve local pattern printing (such as a temperature warning mark) or full coverage printing for personalized design.

[0088] The existing temperature-sensitive color-changing layer 120 can be bonded to the outer surface of the substrate layer 110 by hot pressing, which is beneficial for controlling the distribution of material quality, and can be bonded to a partial area of the substrate layer 110 as needed.

[0089] Specifically, the temperature-sensitive color-changing layer 120 can be provided on a portion of the outer surface of the substrate layer 110 by spraying, printing, or hot pressing. For example, the temperature-sensitive color-changing layer 120 can be provided in temperature-monitoring blind areas such as balsa wood core, PET core, and resin-rich areas.

[0090] In one embodiment, Figure 1 As shown, the bag film 100 further includes a protective layer 130 , which is covered on the outer surface of the temperature-sensitive color-changing layer 120 .

[0091] In actual use, the surface of the bag film 100 may be scratched by tools or other parts. By providing a protective layer 130 on the outer surface of the temperature-sensitive color-changing layer 120, the temperature-sensitive color-changing layer 120 is protected from direct wear and scratching, thereby maintaining the integrity and performance of the temperature-sensitive color-changing layer 120.

[0092] Specifically, the protective layer 130 can be made of polyester film, polypropylene film, polyurethane coating, etc. In the embodiment of the present application, there is no specific limitation on the material type of the protective layer 130.

[0093] In one embodiment, Figure 2 As shown, the temperature-sensitive color-changing layer 120 and the base material layer 110 are co-extruded to form the bag film 100 , and the temperature-sensitive color-changing layer 120 is embedded in the base material layer 110 .

[0094] Multi-layer co-extrusion allows the temperature-sensitive color-changing layer 120 and the substrate layer 110 to fuse with each other at the molecular level to form a tight whole, which can significantly improve the adhesion between the two layers and effectively prevent the temperature-sensitive color-changing layer 120 from falling off or peeling during use, thereby ensuring the stability and integrity of the bag film structure.

[0095] During the multi-layer co-extrusion process, the temperature-sensitive color-changing layer 120 can be evenly embedded in the substrate layer 110, avoiding the situation of local excessive thickness or thinness, ensuring the consistency and stability of the temperature-sensitive color-changing function on the entire surface of the bag film 100, so that the bag film 100 can accurately sense the temperature at different positions and show corresponding color changes.

[0096] The temperature-sensitive color-changing layer 120 is embedded in the substrate layer 110. The substrate layer 110 provides physical protection for the temperature-sensitive color-changing layer 120, protecting it from direct impacts of external environmental factors such as wear, scratches, ultraviolet radiation, and chemical corrosion. This helps maintain the performance of the temperature-sensitive color-changing layer 120, extending its service life and ensuring that it can still accurately respond to temperature during long-term use.

[0097] In addition, multi-layer co-extrusion is a continuous processing technology that can complete the compounding of the temperature-sensitive color-changing layer 120 and the substrate layer 110 in one operation, which greatly improves production efficiency and reduces production costs.

[0098] In one embodiment, the material of the substrate layer 110 is a thermoplastic polymer, which may be any one of nylon, polyethylene, ethylene-vinyl acetate copolymer, or polyester.

[0099] Nylon has excellent mechanical strength and wear resistance, and the bag film 100 made from it can withstand large tension and friction and is not easily broken or damaged.

[0100] Polyethylene has high chemical stability and is not easily corroded. It also has good transparency. The bag film 100 made therefrom allows the wind turbine blades inside the bag film 100 to be clearly seen. When the color of the bag film 100 changes, the operator can technically observe the color change.

[0101] Ethylene-vinyl acetate copolymer has good elasticity and softness, and can be sealed quickly and firmly during the heat sealing process, forming a good sealing effect to prevent the bag film 100 from leaking. At the same time, the high heat sealing strength can ensure the sealing and integrity of the bag film 100 during use.

[0102] Polyester has extremely high transparency and glossiness, as well as high strength, hardness and rigidity. The bag film 100 can withstand greater pressure and weight, is not easily deformed, and can provide reliable support and protection for the items in the bag film 100.

[0103] In one embodiment, the thickness of the substrate layer 110 is 30 μm-150 μm.

[0104] When the base material layer 110 is at least 30 μm thick, it provides sufficient structural support for the bag film 100, giving it excellent tensile strength and tear resistance. It is less likely to break or rupture during use and can withstand items of a certain weight and a certain degree of external force, such as compression and friction. A thickness of no more than 150 μm ensures that the bag film 100 does not become too brittle due to excessive thickness, while maintaining good flexibility and folding resistance, facilitating operations such as folding and sealing. It can also buffer energy by deforming when subjected to external forces, reducing the risk of rupture.

[0105] Among them, the terms "upper" and "lower" are used to describe the relative position relationship of each structure in the accompanying drawings, which is only for the convenience of description and is not used to limit the scope of implementation of this application. Changes or adjustments to their relative relationships should also be regarded as the scope of implementation of this application without substantially changing the technical content.

[0106] It should be noted that, in this application, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or that the first and second features are in indirect contact through an intermediate medium. Furthermore, a first feature being "above," "above," and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0107] Furthermore, in this application, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," "fixed," and the like should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; they may refer to direct connection or indirect connection through an intermediate medium; they may refer to internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in this application based on the specific circumstances.

[0108] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A wind turbine blade vacuum infusion bag film structure, characterized in that: include: At least one bag film (100), the bag film (100) comprising a substrate layer (110) and a temperature-sensitive color-changing layer (120), the temperature-sensitive color-changing layer (120) being disposed on the substrate layer (110) or embedded in the substrate layer (110); The temperature-sensitive color-changing layer (120) is configured to change color in response to temperature changes, and is used to monitor local temperature anomalies during the vacuum infusion process of wind turbine blades. When the temperature of the area covered by the temperature-sensitive color-changing layer (120) exceeds a preset threshold, the temperature-sensitive color-changing layer (120) changes from a first color to a second color, and the first color and the second color are different.

2. The wind turbine blade vacuum infusion bag membrane structure according to claim 1, characterized in that: The temperature-sensitive color-changing layer (120) is a reversible color-changing layer. When the surface temperature of the area covered by the temperature-sensitive color-changing layer (120) decreases from a state exceeding the preset threshold to a state below the preset threshold, the color of the area covered by the temperature-sensitive color-changing layer (120) changes from the second color to the first color.

3. The wind turbine blade vacuum infusion bag membrane structure according to claim 1, characterized in that: The temperature-sensitive color-changing layer (120) is an irreversible color-changing layer. When the surface temperature of the area covered by the temperature-sensitive color-changing layer (120) decreases from a state exceeding the preset threshold to a state below the preset threshold, the color of the area covered by the temperature-sensitive color-changing layer (120) remains at the second color.

4. The wind turbine blade vacuum infusion bag membrane structure according to claim 1, characterized in that: At least two bag films (100) are provided, and at least two bag films (100) are sequentially sleeved; The temperature-sensitive color-changing layer (120) of at least one of the bag films (100) is a reversible color-changing layer, and the temperature-sensitive color-changing layer (120) of at least one of the bag films (100) is an irreversible color-changing layer.

5. The wind turbine blade vacuum infusion bag structure according to any one of claims 1 to 4, characterized in that: The temperature-sensitive color-changing layer (120) is provided on the outer surface of the substrate layer (110).

6. The wind turbine blade vacuum infusion bag membrane structure according to claim 5, characterized in that: The temperature-sensitive color-changing layer (120) is provided on the outer surface of the substrate layer (110) by spraying, printing or hot pressing.

7. The wind turbine blade vacuum infusion bag film structure according to claim 5, characterized in that: The bag film (100) further comprises a protective layer (130), and the protective layer (130) is covered on the outer surface of the temperature-sensitive color-changing layer (120).

8. The wind turbine blade vacuum infusion bag structure according to any one of claims 1 to 4, characterized in that: The temperature-sensitive color-changing layer (120) and the base material layer (110) are formed into the bag film (100) by a multi-layer co-extrusion method, and the temperature-sensitive color-changing layer (120) is embedded in the base material layer (110).

9. The wind turbine blade vacuum infusion bag film structure according to any one of claims 1 to 4, characterized in that: The material of the substrate layer (110) is a thermoplastic polymer.

10. The wind turbine blade vacuum infusion bag membrane structure according to claim 9, characterized in that: The thickness of the substrate layer (110) is 30 μm-150 μm.

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